No visit to Gibraltar is complete without a visit to the 100 Ton Gun which is situated at Napier of Magdala Battery.

The gun was manufactured by Sir W C Armstrong at Newcastle-Upon-Tyne in 1870 and was one of twelve built. Eight were built for the Italian Navy, two were sent to Malta, and two to Gibraltar. The Gun at Napier Battery is the only one in such good condition.

The 17.72 inch Rifled Muzzle loader, or 100 Ton Gun, has a barrel length of 32.65ft, of which 30.25ft are rifled and was capable of firing up to 8 miles. Hydraulic power generated by a steam engine was used to elevate and traverse the Gun. It took a minimum of 3 hours to develop the necessary head of steam to operate the mounting though this was quite acceptable since it took a Man O'war at least 3 hours to enter the bay of Gibraltar after being sited off the point of Tarifa in Spain.

The Gun, which actually weighed 100.2 tons, projected a 2000lb shell with a muzzle velocity of about 1540 feet per second. This required 450lbs of black prism gun powder which gave the projectile a smashing effect of 33,230ft/ton, allowing it to penetrate 24.9 inches of wrought iron. The normal rate of fire of the Gun was a round every four minutes and it required 35 men of all ranks to serve the Gun.

It is said that during a visit of the Inspector-General of Artillery in 1902 the Gun was prepared to fire 5 rounds at full charge. On the first order to fire, the tube fired but that was all. After further attempts still nothing happened so the misfire drill was carried out but to no avail. At the end of the stipulated 30 minutes wait, the General asked for a volunteer to go down the bore and fasten the shell extractor to the projectile so that the Gun could be unloaded. After a long pause for consideration a small thin soldier stepped forward and volunteered for the task. Stripped to the waist, a rope round him and the extractor ready, he was himself 'loaded' into the Gun. A few moments later, to everyone's relief, he was hauled back safely, having completed his task. The gunner's reward, though not princely, was immediate, as it is said that he was promoted to the rank of Bombardier that same day.

An interpretation centre was inaugurated on location in October 1994 which offers visitors the opportunity of discovering much more information and interesting facts about this unique 100 Ton Gun.